The term Pentecost comes from the Greek term meaning “fiftieth,” in reference to the fiftieth day after the start of the Passover festival in early spring. In Hebrew, Pentecost is known as Shavuot, or the Festival of Weeks. Shavuot is a biblically mandated festival marking the conclusion of the springtime grain harvest. For this reason, it is also referred to as the Festival of the Harvest (Exod 23:16) and the Day of the First Fruits (Num 28:26).
In the first century C.E., Shavuot, along with Passover (Pesach) and the Feast of Tabernacles (Succoth), was primarily an agricultural festival, culminating in a pilgrimage to the Jerusalem temple. Loaves of bread would be made from the harvested wheat and offered at the temple. In early rabbinic texts, Shavuot took a backseat to Passover and Succoth. It is unclear how much of the Jewish population would have attended the festivities in Jerusalem during the Second Temple period, since frequent travel would have been difficult, especially for those in the more remote areas of Galilee, the Golan, and the Diaspora. The writings of Flavius Josephus suggest that Shavuot was the least well-attended of the three pilgrimage festivals. Nevertheless, according to Josephus, the mass gathering in Jerusalem during Shavuot in 4 B.C.E. occasioned a riot against the local Roman procurator, resulting in considerable loss of life (Jewish Antiquities 17.221-268; Jewish War 2.42-44).
There is evidence, however, suggesting that for some Jews during the Second Temple period Shavuot was the most important and holiest of the three pilgrimage festivals. In the book of Jubilees, Shavuot is celebrated as the annual renewal of the covenant between God, on the one hand, and Noah, the patriarchs, and Moses on the other. Shavuot may have had special significance for the authors of the Dead Sea Scrolls, as well.
The theme of an annually renewed covenant carried over into early Christian interpretations, associated with Acts 2:1-11. Over the centuries, Christians have celebrated Pentecost fifty days after Easter, to commemorate the receiving of the Holy Spirit by followers of Jesus.
Among Jews, rabbinic traditions have associated the holiday with the revelation on Mount Sinai and the giving of the Torah by God to Moses. Today, the holiday is known alternatively as hag matan torateinu, the Festival of the Giving of Our Torah. Jewish tradition has also associated the holiday with the birth and death of King David.